1. Field of the Invention
The present invention relates to hearing aids. The invention, more specifically concerns a custom earplug for a hearing aid, adapted for engagement with an earpiece.
2. The Prior Art
WO-A1-2007006302 discloses a BTE hearing aid comprising a housing, an earpiece and a custom earplug. The word custom signifies that the earplug is adapted to fit the ear canal of an individual hearing aid user. The earpiece has a connector for cooperation with a socket of the custom earplug. The connector and the earpiece have means for snap fitting engagement and means for defining the mutual rotational orientation. The connector may comprise at least one locking means so that the connector can be smoothly positioned when pressed into place and so that a larger force is needed for pulling the connector out of the engagement. The connector may further comprise a guide that secures that the earpiece and the earplug are mounted in the right mutual position. The guide may be formed as a slit. The earplug may comprise a stop for positioning the connector in the earplug. In a preferred embodiment the stop is a shoulder preventing the connector from being pressed too far into the earplug.
The aim of this invention is to improve the design of such an earplug in order to allow the use of earpieces made of materials with a comparatively high hardness without requiring strict manufacturing tolerances. Hard materials may be advantageous with respect to e.g. higher transparency and enhanced bio-compatibility. However, snap fitting engagement means designed for use with two specimens made from materials of a relatively high hardness require strict manufacturing tolerances.